<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>圆</title>
		<style>
			div{
				width: 100px;
				height: 100px;
				border: 4px solid red;
				border-radius: 50%;
				box-shadow: 20px 10px 10px #00FFFF;
			}
		</style>
	</head>
	<body>
		<div></div>
	</body>
</html>
